Solve for $x$ and $y$ using substitution. ${-4x+2y = 12}$ ${y = -x+9}$
Answer: Since $y$ has already been solved for, substitute $-x+9$ for $y$ in the first equation. ${-4x + 2}{(-x+9)}{= 12}$ Simplify and solve for $x$ $-4x-2x + 18 = 12$ $-6x+18 = 12$ $-6x+18{-18} = 12{-18}$ $-6x = -6$ $\dfrac{-6x}{{-6}} = \dfrac{-6}{{-6}}$ ${x = 1}$ Now that you know ${x = 1}$ , plug it back into $\thinspace {y = -x+9}\thinspace$ to find $y$ ${y = -}{(1)}{ + 9}$ $y = -1 + 9$ $y = 8$ You can also plug ${x = 1}$ into $\thinspace {-4x+2y = 12}\thinspace$ and get the same answer for $y$ : ${-4}{(1)}{ + 2y = 12}$ ${y = 8}$